Semaglutide and beta-cell function in T1D

A case study published in Diabetes/Metabolism Research and Reviews in July 2026 reports that a patient with newly diagnosed type 1 diabetes maintained stable blood sugar control and preserved beta-cell function while receiving semaglutide alongside standard insulin therapy^[1]. The finding adds to a small but growing body of evidence suggesting that GLP-1 receptor agonists may help extend the window during which newly diagnosed type 1 patients still produce some of their own insulin.

What the case study describes

The authors, based at institutions in Verona, Milan and Padova, describe a patient who began semaglutide treatment shortly after receiving a type 1 diabetes diagnosis. The study tracked glycaemic control (measured by HbA1c) and beta-cell function (measured by C-peptide, a marker of the body's own insulin production) over the treatment period^[1].

In type 1 diabetes, the immune system destroys insulin-producing beta cells in the pancreas. Most people still have some working beta cells at the time of diagnosis, a phase sometimes called the "honeymoon period." During this window, patients may need less injected insulin because their pancreas is still contributing. The honeymoon period typically fades within months to a few years as beta-cell destruction continues.

C-peptide is a byproduct of insulin production. When the pancreas makes insulin, it splits a precursor molecule called proinsulin into insulin and C-peptide in equal amounts. Measuring C-peptide in the blood therefore provides a reliable indicator of how much insulin the body is still making on its own, separate from any insulin that has been injected.

The case report suggests that semaglutide may have helped sustain this residual beta-cell function, as reflected by maintained C-peptide levels and glycaemic control that held steady rather than deteriorating in the pattern usually seen after diagnosis^[1].

Earlier evidence from a larger case series

This Italian case study follows a 2023 report from the University at Buffalo published in the New England Journal of Medicine. That study tracked 10 adults (aged 21 to 39) who started semaglutide within three to six months of their type 1 diagnosis^[2]. Within three months, all 10 patients had stopped mealtime insulin injections. By six months, seven of the ten had also discontinued basal insulin. Mean HbA1c dropped from 11.7% at diagnosis to 5.9% at six months and 5.7% at 12 months.

A separate five-year case study from the University of Udine followed a 36-year-old woman with adult-onset autoimmune diabetes (classified as type 1 diabetes endotype 4) who received semaglutide plus metformin instead of insulin. Her C-peptide levels remained stable or increased over 60 months of follow-up, and her HbA1c stayed below 7% for most of that period^[3]. These observations, while limited to a single patient, suggest that the beta-cell protective effect may persist over years in selected cases.

Why GLP-1 receptor agonists might protect beta cells

GLP-1 receptors are present on pancreatic beta cells. When activated, they stimulate insulin secretion in a glucose-dependent manner, meaning the effect ramps up when blood sugar is high and tapers off when it is normal. Beyond this direct action, preclinical research suggests GLP-1 receptor agonists may also promote beta-cell survival by reducing apoptosis (programmed cell death) and encouraging cell proliferation through transcription factors such as PDX-1 and MafA^[4].

A 2024 review in the International Journal of Molecular Sciences noted that GLP-1 receptor agonists may also dampen the inflammatory response that drives beta-cell destruction in type 1 diabetes, regulating pro-inflammatory cytokines such as TNF-alpha, IL-6 and IL-1 beta while supporting regulatory T cells involved in immune tolerance^[4].

What this does not tell us

A single case study cannot establish that semaglutide reliably preserves beta-cell function in type 1 diabetes. The Buffalo case series involved only 10 patients with no control group, and the Udine report followed one individual. None of these are randomised controlled trials, so it remains unclear whether the observed outcomes reflect a genuine drug effect, natural variation in the honeymoon period, or other factors such as patient selection.

There are also safety considerations specific to type 1 diabetes. Reducing insulin doses in patients who depend on exogenous insulin carries a risk of diabetic ketoacidosis (DKA), a potentially life-threatening condition. Gastrointestinal side effects (nausea, vomiting, appetite loss) are common with semaglutide and could complicate nutritional management in patients who are already adjusting to a new diagnosis.

Semaglutide is approved for type 2 diabetes and chronic weight management, not for type 1 diabetes. Any use in type 1 patients is off-label and should only be considered under close medical supervision. If you have been recently diagnosed with type 1 diabetes, talk with your endocrinologist about evidence-based treatment options.